Southern California -- this just in

Two more L.A. water mains burst overnight, bringing more questions

Two more water mains broke overnight in the San Fernando Valley, the latest in a rash of problems hitting L.A.'s water system.

The first break occurred around 2:30 a.m. on Corbin Avenue in Warner Center, sending water into the street. The second break occurred around 4:30 a.m. on Burbank Boulevard in Winnetka.

Both incidents are under investigation.

Underground water pipes in Los Angeles have suffered significantly more "major blowouts" in the last three months, officials confirmed Tuesday after analyzing dozens of ruptures, some of which flooded streets, damaged vehicles and buildings and, in once case, created a sinkhole so big that it almost swallowed a firetruck.

And the city's engineers don't know why.

It could be fluctuating temperatures. It could be a statistical anomaly. It could be something else.

"It's strange," said William Robertson, general manager of the Bureau of Street Services, which repaves the ruined roads after the water recedes. "The thing that is puzzling is they are so spread out . . . all over the city. You can't link them to anything."

What Department of Water and Power officials can say with certainty is they want more money to fix the problem and plan to ask for a water rate hike. The blowouts underscore the fact that the city's aging water system, which has 7,200 miles of pipe and moves 600 million gallons of water a day, needs an upgrade, officials said.

"This all requires a lot of money," said Jim McDaniel, head of the city's water system.

But some City Council members, who would have to approve any rate increase, did not appear convinced.

"They have to make a case for that," said Councilwoman Jan Perry. She added that she is concerned about the rise in blowouts. "We have to get to the cause," she said. "People can get hurt. Property can be lost."

Los Angeles' water system was put in place by William Mulholland, who figured out how to tap water from the Eastern Sierra and the Owens Valley and designed an aqueduct system that let it flow to Los Angeles on the force of gravity alone.

The influx allowed semi-arid Los Angeles to boom -- and subdivisions marched outward in the 1920s and the years just after World War II.

The system remains a marvel to many engineers and still sends water over the Santa Monica Mountains from Sylmar to San Pedro using gravity. But parts of it are now almost 100 years old, and many of the pipes are wearing out. At the same time, new water quality standards are requiring the DWP to cover many reservoirs at great expense.

The age of the pipes has long been a concern to engineers and officials at the DWP, but most Angelenos were unaware of the urgency until earlier this month.

On Sept. 5, a 95-year-old trunk line ruptured under Coldwater Canyon Avenue, sending a torrent of mud and water shooting 10 feet into the air and into the streets of Studio City.

Less than 72 hours later, a broken main created a sinkhole not far away in Valley Village -- and nearly consumed a firetruck that responded. Days later, another broken main flooded Melrose Avenue near Fairfax High School.

And on Tuesday, there was another on Exposition Boulevard, which caused officials to close the thoroughfare between Crenshaw and Degnan boulevards and cut off water to several businesses.

-- Jessica Garrison

Photo: Department of Water and Power workers drain a sinkhole on Burbank Boulevard east of De Soto Avenue in Woodland Hills early this morning. Credit: Al Seib / Los Angeles Times